He explained that was because under the contract, if just one doctor worked over 48 hours, everyone in the medical team got an equivalent ‘overtime’ payment for that week.

He said: That team could include six or seven people. New Deal makes it punitively expensive to have junior doctors working more than 48 hours a week. It’s a major stumbling block.

“The college is worried about the impact these restrictions have on doctors’ training and the care they provide to patients.”

The problems were “keenest felt” overnight and at weekends in county town district general hospitals, he said, which faced recruitment problems.

“Trying to run a rota on 48 hours is extremely difficult, particularly if you’ve got vacancies,” he said.

“It things don’t change, there the potential for the smaller hospitals to be unable to provide a safe out-of-hours emergency service.”

Speaking in response to the RCP’s Hospitals on the Edge report, a Department of Health spokesman said: "As a result of these challenges, the Coalition Government believes that the European Working Time Directive needs to be revised across the EU so our NHS has the flexibility it needs to support doctors in training and to provide proper continuity of patient care. Negotiations are already underway.”

He continued: “We are exploring whether the current Junior Doctors’ contract, developed over 20 years ago, still fits the needs of a modern NHS in ensuring high quality training, sensible working hours and high standards of patient care."

But Dr Tom Dolphin, chairman of the British Medical Association’s junior doctors’ committee, said: “Knowing what we know about longer hours leading to higher human error rates, it simply would not be right to call for junior doctors to be working longer hours again.”